• The recent four-player Yankees-Mariners trade likely will be debated for years.

One good sign for the Mariners: Diamondbacks GM Kevin Towers, who worked for the Yankees in 2010, is a fan of right-hander Hector Noesi, who went to the Mariners with catcher Jesus Montero for righty Michael Pineda and minor-league righty Jose Campos.

Towers, renowned for his pitching expertise, asked for Noesi as part of a trade package when he spoke with the Yankees about outfielder Justin Upton after the ’10 season, according to a rival executive.

• The obvious benefit of the Nationals’ failure to sign free-agent first baseman Prince Fielder is that it allows the team to retain positional flexibility, particularly in center field.

A long-term deal for Fielder eventually might have forced the Nats to use an outfield of Michael Morse in left, Jayson Werth in center and Bryce Harper in right. Without Fielder, they can move Morse to first after Adam LaRoche plays out his contract this season and pursue a legitimate center fielder.

Michael Bourn, Shane Victorino and B.J. Upton are eligible for free agency next offseason, and the Nats also are high on three of their center-field prospects – Brian Goodwin, Michael Taylor and Eury Perez.

None, though, has yet to play above Class A.

Goodwin, the 34th overall pick in last year’s draft, is the team’s fifth-ranked prospect, according to Baseball America. Taylor, who draws comparisons to Mike Cameron, took perhaps the biggest jump of any player in the system last season. Perez is a speedster with offensive potential.

• As I reported on Twitter earlier this week, the Cubs, Marlins and Tigers are the three clubs scouting Cuban outfielder Yoennis Cespedes most closely in the Dominican.

Cespedes finally hit the open market Wednesday. The bidding for him is certain to be intense, if for no other reason than the new spending limits on international amateur talent will limit clubs in most foreign markets. (Cuban defectors and Asian players who are older than 23 and have more than five years professional experience will not be subject to the restrictions.)

Starting with the 2012-13 signing season, each club will be allocated a signing-bonus pool. The pools will be equal in 2012-13, then will vary based on reverse order of winning percentage thereafter. Clubs that exceed their respective limits will be subject to penalties.

• Remember Kosuke Fukudome?

He remains a free agent, and the Brewers showed interest in him before paying a combined $4.75 million for Japanese outfielder Norichika Aoiki — a $2.5 million posting fee and a two-year, $2.25 million contract.

Fukudome, who had a combined .712 OPS last season for the Cubs and Indians, wants to remain in the majors, according to a source with knowledge of his thinking. Some executives, however, believe he may end up back in Japan.

• Speaking of Japanese players, Rangers right-hander Koji Uehara had such a positive experience in Baltimore, he recommended the Orioles to the two free-agent lefties the team signed out of the Japanese league, Tsuyoshi Wada and Wei-Yin Chen, according to a major-league source.

Uehara invoked his limited no-trade protection to reject a deal to the Blue Jays this week, sources say, prompting the Jays to sign free-agent righty Francisco Cordero to a one-year, $4.5 million contract.

A trade back to the Orioles is a possibility.

• The Red Sox are talking to free-agent right-hander Edwin Jackson, who could be open to a one-year deal.

Two years ago, agent Scott Boras negotiated such a “pillow” contract with the Red Sox for another of his clients, third baseman Adrian Beltre.

One executive, however, points out that the AL East offers no such soft landing for a starting pitcher. If Jackson signs for one year, he might be better off in the NL, where he could produce better numbers before going back into the open market.

Yankees: At last check, they had yet to upgrade their starting rotation. Ubaldo Jimenez is one physical exam from becoming a Cleveland Indian, and Hiroki Kuroda isn’t going anywhere. Do you really think the Yankees are going to sit this one out?

Braves: Carlos Beltran and Hunter Pence landed elsewhere, and the Braves still need a center fielder. Will they swing a deal for B.J. Upton, Michael Bourn, Coco Crisp – or someone else?

Rangers: Yes, they swung a deal for Koji Uehara. But what about Heath Bell?

White Sox: Kenny Williams is downplaying the chances for a major trade … which only heightens the intrigue. Despite hints at a possible shakeup, the White Sox are 5-2 in their last seven games. After moving Edwin Jackson, they’re interested in adding rotation depth at a low cost – a Bruce Chen type, perhaps.

Red Sox: Much like their rivals in the Bronx, the Red Sox haven’t made a significant pitching upgrade. And Theo Epstein is the type of general manager who won’t be afraid to make a big move right at the deadline.

Twins and Nationals: We’re all waiting on the Denard Span for Drew Storen trade.

Padres: They have a lot of bullpen inventory ready to move, not to mention outfielder Ryan Ludwick and starter Aaron Harang. The sale should start any minute now.

Check back with FOXSports.com and on Twitter (@Ken_Rosenthal and @jonmorosi) for updates throughout the day.

Bourn, in particular, should be discussed in depth between now and Sunday’s 4 p.m. ET non-waiver trade deadline. The Nationals, Braves, Indians and Reds are among the clubs with varying levels of interest in Bourn, major-league sources say. The Nationals, looking everywhere for a center fielder, also have discussed Denard Span with the Minnesota Twins in recent days.

But in marketing Bourn to other clubs, the Astros will be competing against an available player at the same position who has much greater power potential: Tampa Bay center fielder B.J. Upton.

Bourn, 28, is regarded as a true leadoff man. He bats from the left side and has a .769 OPS this season to go along with a league-best 39 stolen bases in 104 games.

Bourn is earning $4.4 million this season and will receive a raise through salary arbitration in 2012 before becoming a free agent. Bourn is a Scott Boras client, so interested clubs will likely view him as a 1 ½-year acquisition.

If the Astros move Bourn, it’s logical that they would ask for a potential everyday center fielder in return. Among players on the active roster, Jason Bourgeois would be Bourn’s likely replacement. Bourgeois, 29, is having a career year, with an .836 in 52 games.

The Braves didn’t get Carlos Beltran or Hunter Pence, but they remain almost certain to land an outfielder before the non-waiver deadline at 4 p.m. ET Sunday.

It’s just a matter of which one.

The Braves are pursuing both center fielders such as B.J. Upton and Michael Bourn and corner outfielders such as Ryan Ludwick, Carlos Quentin and Josh Willingham, major-league sources say.

Upton, a right-handed hitter, might be the best fit. The Braves can commit more at-bats to a center fielder. And Bourn, like the Braves’ two injured center fielders, Jordan Schafer and Nate McLouth, is left-handed.

If the Braves add a center fielder, he likely will supplant Schafer, an elite defender who is not yet an established hitter. But if they add a corner outfielder, it will a tighter fit.

Right fielder Jason Heyward could sit against left-handers — he entered Friday batting .167/.255/.310 against lefties, .247/.335/.442 against righties. Chipper Jones also could rest on occasion, with Martin Prado moving to third to open up left.

The Braves wanted Beltran, but were unwilling to part with left-hander Mike Minor, one of their top pitching prospects, for a two-month rental, according to a source.

The Braves also wanted Pence, but the price was higher for a player under club control through 2013; the Astros wanted two of the Braves’ top four young pitchers plus a third quality arm, the source said.

If the Braves seem overly protective of their pitching prospects — Minor and righties Julio Teheran, Arodys Vizcaino and Randall Delgado — it’s because they might need several of those pitchers soon.

Righties Derek Lowe and Tim Hudson will enter the final years of their contracts next season (the Braves hold a $9 million option on Hudson for 2012).

Righties Jair Jurrjens and Tommy Hanson, meanwhile, are getting more expensive — both are arbitration-eligible and represented by Scott Boras, who prefers his clients to establish their market value in free agency rather than sign contract extensions.

However, the Twins likely would want better than a right-hander such as Todd Coffey or Henry Rodriguez in a package for Span.

In addition to Upton and Span, the Nats also are looking at the Cardinals’ Colby Rasmus and Astros’ Michael Bourn sources say.

The team considers Desmond a player with promise, but his .584 OPS is the lowest in the National League. Some club officials want to move second baseman Danny Espinosa to short and promote Steve Lombardozzi to second.

Span, 27, is under a club-friendly contract – he is earning $1 million this season, $3 million next season, $4.75 in 2013 and $6.75 million in ’14 with a $9 million club option for ’15.

The concern with Span is that he has not played since June 6 due to a concussion. He currently is on a rehabilitation assignment.

A year ago at the non-waiver trade deadline, the Washington Nationals hit the jackpot, trading a reliever, right-hander Matt Capps, for a potential All-Star, catcher Wilson Ramos.

Might history repeat?

Numerous teams are calling on the Nationals’ two top relievers, closer Drew Storen and setup man Tyler Clippard, as well as a lesser right-hander, Todd Coffey, major league sources said.

The Nats are listening on Storen and Clippard, but will trade one of them only if they can improve long-term by filling a specific need, according to one source with knowledge of the club’s thinking.

The team’s No. 1 goal is to add a center fielder, preferably one who could bat leadoff. Potential targets include the B.J. Upton of the Tampa Bay Rays, Michael Bourn of the Houston Astros, Colby Rasmus of the St. Louis Cardinals and Denard Span of the Minnesota Twins, sources said.

A reliever alone – even one as good as Clippard or Storen – probably would not be enough to bring back a center fielder. The Nats, though, also are getting calls on second baseman Danny Espinosa and shortstop Ian Desmond, sources said.

The team will not trade Espinosa, a candidate for National League Rookie of the Year.

Desmond could be another story.

The Nats, if they traded Desmond, would be selling low; his .580 OPS is the worst in the NL. Club officials also are reluctant to give up on Desmond, whom they view as an improving defender, emerging leader and hitter capable of hitting .280 with 12 home runs and 70 RBI.

However, another dynamic is in play.

Some club officials would like to move Espinosa to short and promote Triple-A second baseman Steve Lombardozzi to play second, sources say.

Lombardozzi — the son of former major league infielder Steve Lombardozzi — has a combined .815 OPS at Double-A and Triple-A.

Desmond, who turns 26 on Sept. 20, ultimately could evolve into a super-utility man for the Nats. But several contenders are weak at short, and few quality players are available at the position.

The Baltimore Orioles just signed J.J. Hardy to a three-year extension. The New York Mets appear unlikely to trade Jose Reyes.

Desmond, even with his offensive regression, would qualify as an upgrade for teams such as the Minnesota Twins, San Francisco Giants and Milwaukee Brewers.